Machine for grinding and polishing blocks of stone



Sept. 25, 1951 R. H. DAVIS 2,569,291

MACHINE FOR GRINDING AND POLISHING BLOCKS OF STONE Filed Dec. 14, 19492Sheets-Sheet 1 1N VEN TOR. R/cHA/w fl .DHl/l s Sept. 25, 1.951 R. H.DAVIS 2,569,291

MACHINE FOR GRINDING AND POLISHING BLOCKS 0F STONE Filed Dec. 14, 1949 II 2 Sheets-Sheet 2 1 IN VEN TOR. R/CHHRD DH v/s Patented Sept. 25, 1951MACHINE FOR GRINDING AND BLOCKS OF STONE POLISHING Richard H. Davis,Rutland, Vt.,. assignor to Lin-- coln Iron Works, Rutland; Vt, a,corporation of Vermont Application December 14, 1949, Serial No. 132,933

This invention relates to machines for grinding and polishing. blocks.of. stone as commonly used for architectural or: memorial purposes. Insuch. machines, a grinding and polishing wheel is rotatedabo-utavertical. axis as it rests freely upon the surface to be finished, andan abrasive or polishing material is fed, between the, wheel and thework during the finishing operation. The wheel. must be so, mounted thatit can be moved about freely over the surface to be finished.

It is the general object of my present invention to improve theconstruction of such machines as heretofore known, to the intent thatmore convenient and satisfactory operation may be attained.

To. the accomplishment. ofthis general object, I provide improved meansfor raising and lowering the Wheel and motor assembly relative to thework, together with. an improved construction by which the downward.pressure of the. Wheel on the work may be conveniently varied to meetoperating conditions.

I also provide improved; means. for maintaining the wheel parallel to.the; work surface over a substantial range in elevation.

My invention further relates to arrangements and combinations of partswhich will be. hereinafter described and more particularly pointed outin the appended claims.

A preferred form of the invention is shown in the drawings, in which 7Fig. 1 is a plan view of my improved grinding and polishing machine;

Fig. 2 is a front elevation thereof, looking in the direction of thearrow 2 in Fig. 1;

Fig. 3 is a side elevation, looking in the direction of the arrow 3 inFig. 1;

Fig. 4 is a detail sectional plan view, taken,

along the line 4-4 in Fig. 3; and

Fig. 5 is a rear elevation, looking in the direction of the arrow 5 inFig. 1 but showing a modified construction.

Referring to Figs. 1 to 4, I have shown my improved machine inassociation with a block of stone S supported on any suitable foundationin a bin B.

The grinding and polishing wheel W rests upon the horizontal uppersurface of the block of stone S and is continuously rotated by a motor Mthrough pulleys l0 and H and a multiple belt l2. The pulley II ismounted at the upper end of an upright shaft l4, rotatable in a bearingwhich is secured to one end of a heavy tubular member I6. The motor M irigidly mounted at the opposite end of the member 16.

The wheel W is connected to the upright shaft I4 through a swivel devicel8 which'permits the wheel to adapt itself to the surface of the work.The tubular member l6 has a short shaft or 2 Claims. (01. 51 -126) stud20 (Fig. 3) fixed to the under side thereof andat an intermediate pointin its length. The: shaft 20 is mounted anti-friction bearings 2|: in abearing block 22 (Fig. 4), having a gudgeon. 24 swiveled in a bearing 25in the free end of. a tubular supporting arm 30. Angular movement of thegudgeon 24 is limited by stop surfacesZii.

The right-hand end of the arm 36 as viewed.

in Fig. 2 is pivoted at 3| to a sleeve 33 which is rotatably mounted onan upright stud 35- which is fixed to a stand or bracket 36- Which isrigidly secured as by bolts 31 to a foundation block orpost F. The standBit-may be braced by flanges. 38.

With this construction, the arm It may swing freely on its stud or shaft2!], as indicated by the. double arrow a in Fig. 1, and the arm 30 mayalso swing freely on its fixed upright shaft 35, as. indicated by thedouble arrow b in Fig. l. The; tubular member 16 also has limitedangular: movement. about the axis of the gudgeon 24.

A weight 50 (Fig. 3) is slidably mounted on the tubular member 16 andmay be shifted axiall of said member by a handle 52 which is con-'nected to move the weight back and forth by means of a cord or cable54.By thus shifting the weight 50, any desired downward pressure of thewheel W on the stone S may be conveniently attained by the operatorwithout moving from his Working position. A hand rail 55 is associatedwith the grinding shaft bearing i5 and may be conveniently used inmoving the wheel back and forth.

Special provision is made for raising and lowering the motor and wheelassembly by swinging the supporting arm 30 upward or downward.

For such purposes, a double bell crank 6!! is pivoted at 6| to the underside of the member 30. The short arm of the bell crank 60 is connectedby links 62 to a pivot stud 63 on the upper part of the sleeve 33, andthe long arm of th bell crank 60 is connected to a rod 56 which isassociated with a piston '6'! slidable inside of a cylinder 68 having apivotal connection 59 to the arm 30.

When air or water pressure is applied through the pipe III, the piston6'! will be moved outward or to the right in Fig. 2 and the supportingarm 3|] will be caused to swing upward about its pivot 3|, thus raisingthe wheel W from the stone S. Any suitable control valve V (Fig. 1) maybe conveniently positioned adjacent the operators station.

If a machine is to be successively used on pieces of work ofsubstantially different thickness, it is desirable to provide formaintaining the short shaft 20 in vertical position, regardless of theangular position of the supporting arm 30. This result may be attainedby using the construction 3 shown in Fig. 5, in which the bearing block80 for the upright shaft 20 is pivoted at 8| to a member 82 which isfixed at the outer end of a supporting arm 30a.

The bearing block 80 has an upwardly extending arm 84, connected at 85to alink 86 which in turn is pivoted on the stud 63 on the sleeve .33 towhich the link 62 is also connected. The pivot points 3|, 63, 85 and BI(Fig. define a parallelogram, which insures that the shaft 20 willremain vertical in every operating position of the supporting arm 30a.

The somewhat simpler construction shown in Fig. 4 is found satisfactorywhere the upper surface of the stone S does not vary substantially inelevation, so that the parts always assume substantially the positionindicated in Fig. 2 when the machine is in operation.

A grinding and polishing machine constructed as herein shown anddescribed may be very conveniently operated and has been found reliableand satisfactory in use. The provision of the cylinder 68 and associatedparts permits the wheel to be raised from the Work or lowered thereon bysimple operation of the valve V, and the pressure of the wheel on thework is quickly and easily adjusted by shifting the Weight 50 on thetubular member [6.

Having thus described my invention and the advantages thereof, I do notwish to be limited to the details herein disclosed, otherwise than asset forth in the claims, but what I claim is:

1. In a grinding and polishing machine, a fixed upright post, a bearingsleeve rotatable on said post, a radial supporting arm pivoted to saidsleeve to swing vertically thereon, a fluid-operated cylinder-and-pistoncombination pivoted to said supporting arm, means to supply operatingfluid to said cylinder, a bell crank pivoted on said supporting arm, alink connecting the short depending arm of said bell crank to the top ofsaid bearing sleeve, said bell crank also having a long andupwardly-extending arm connected to said cylinder-and-pistoncombination, whereby outward movement of said piston in said cylinderwill efiect upward swinging movement of said supporting arm, a cross barpivoted intermediate its ends to the free end of said supporting arm andhaving limited angular movement only on said arm, a work-engaging wheelmounted at one end of said cross bar, a motor mounted at the other endof said cross bar, and driving connections between said motor and wheel.

2. The combination in a grinding and polishing machine as set forth inclaim 1, in which a bearing block is mounted on a transverse pivot at.the free end of said supporting arm and is itself provided with anupright arm, and in which a link connects the upper end of said uprightarm to a point at the upper end of the bearing sleeve and therebymaintains the axis of the bearing opening in said block substantiallyvertical as said supporting arm is swung upward and downward, and inwhich a transversely-projecting stud on said cross bar extendsdownwardly and is pivoted in said bearing block to swing transverselyabout said substantially vertical axis.

RICHARD H. DAVIS.

REFERENCES CITED The following references are of record in the file ofthis patent:

V UNITED STATES PATENTS Number Name Date 390,926 Warth Oct. 9, 1888931,383 Cavicchi Aug. 17, 1909 1,044,423 Rosa Nov. 12, 1912 1,501,327Fox July 15, 1924 1,725,899 Chase Aug. 27, 1929 1,999,138 Mason Apr. 23,1935 2,073,400 Cumming Mar. 9, 1987 2,089,808 Ocenasek Aug. 10, 19372,285,808 Cumming June 9, 1942 FOREIGN PATENTS Number Country Date 3,220Great Britain 1901 356,884 Italy Feb. 19, 1938

